Valve tappet



G. R. RICH VALVE I'APPET Filed Oct. 19, 1925 juf vz, ,Kf Zxmm ,by i .5.,5

0 n l 5v x Y Patented Aug. 3, '1926. I

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PATENT' -eFuCE-f. j

enonen a.. Bren, 'or :BATTLE canna, MICHIGAN.

Application med October 19, 1925.A Serial No. 63,456.

the bearing face of the head, as this often raises the temperature ofthe tappets suffi-l ciently to soften one made of ordinary steel,

with the result that grooves are worn into.

the bearing face of the tappet and it becomes noisy and useless. Highspeed steel4 or other high heat resisting alloys are very desirable fortappets, but such metals are exceedingly costly Aand are not essentialin the stem'portion. Great diiiiculty has been encountered inmanufacturing two piece tappe'ts, of which the head portion is mafie ofahigher heat resisting alloy than the stem portion, because of the highheat required for heating-the head portion to a forging temperature.Forged, headed articles' made from two pieces of metal, of which theexterior metal of the head portion exceeds the quantity of metalv of thestem contained in the head, may be successfully united by a forgingprocess, that I have developed for use in the manufacture of poppetvalves,`but when the metal of the portion of the stem which enters thehead, exceeds the amount of metal contained in the exterior portion ofthe head, it is practically impossible `to produce an operative device,because the metal of the stem takes the shape of a ball or enlargementof irregular and incontrollable form when the parts are forged int'oshape, and

the exterior metal remains loose on the stem, which is fatal to a tappetor analogous article. I have manufactured two piece valve tappets usinghollow stems and have found that in the manufacture thereof, especially7wherethe metal of the head portion Wasl made of high speed steel orsteels of the same general character, that sometimes the exterior metalof the head portion would shear or pinch off the metal of the thin webwhich enters the head. l

From .my experiments, I have discovered that the amount of the materialcontained in the interior part of the head must not exceed thatcontained in the exterior portion, otherwise only moderately goodresults are obtained. I have also discovered that if the quantity ofmetalof the interior part of the `head is less than that of the exteriorportion and that if a solid abutment is provided for the exterior partof the head to bear against when the parts .are being forged up, thatthe metal of 'the stem is spread' evenly throughout the exterior part ofthe head and that the twopiecesbecome fused togetherA forming anintegral piece. The result is thata practical, highly eflicient valvetappet 1s produced which has the high heat resisting qualities necessaryfor, the head and which can be made economically and which are light,rugged and durable.

, The invention consists-in a valve tappet vor analogous article madefrom'two pieces of metal, which-may be ofrdiiferent kinds of material,the stem portion having a solid end 'part against which the exteriorportion of the head abuts and having an annular, widely spreading,relatively thin iin pro-` jecting laterally into that part of the headwhich overhangs the stem, and fused thereto. It further consists in aforged two piece valve tappet or analogous article' made from two piecesof metal, that may -be composed of different materials, the stem havinga concave, solid end fportionterminating in an annular, widely flaring,relatively thin iin extending laterally into the exterior portion of thehead, the headhaving a convex portion conforming to the concave endYp0rtion of the stem 'and the stem and head being fused together during.the forging operation.v The invention further consists in 'A the severalnovel features hereinafter fully set forth and claimed.

'Ihe invention is clearly illustratedin the drawing accompanying thisspecification, in which: p

Fig. l is a side elevation of a valve tappet embodying a simple form ofthe present i`nvention; Fig. 2 is a central longitudinal sectionthereof; Fig. 3 is an end view looking at the head portion and-showingthe same partly broken out; Fig. 4 is a central vertical sectionillustrating dies in which the tappet is shaped up and showing the twopieces or blanks from which the tappet is made; Fig. 5 is an enlargedcentral vertical section of a fragment of the blank which forms the stemportion and the blank which forms the exterior portion of the head andin dotted lines, showing the parts `in the form they assume whenoperated upon by the forging dies; Fig. 6 is an end view of the b ansimple form of the present invention.

which forms the exterior portion of the khead and Fig. 7 is an end viewof the blank which forms the stem portion.

Referring to said,drawing, the reference character 10 designates thestem and 11 the disc like head of a valve tappet embodyixrilgha egreater part of the stem may be bored out as at l2 to provide a hollowtappet stem. .The bored portion may be threaded as at 13 for thereception of the adjustment stud (not shown), which is usually used inconnection with valve tappets. If desired, the end of the stem adjacentthe head may be slightly reduced in diameter to provide a neck likearrangement 14, and the other end of the stem may also be slightlyreduced in diameter as at 15 and it is made flat as at 16 t0 permit awrench to be applied thereto when adjusting the adjustment stud.

The stem 10 and the exterior portion of the head l1 are composed of twoinitially separate pieces of metal, shaped up and united by a forgingprocess, and as a reference the exterior portion of the head 1s composedof an alloy of high heat 4resisting characteristics such for instance ashigh speed steel or other alloys containing tungsten. The stem may bemade of straight steel or high grade steel alloys. Usually the stem of avalve tappet is of a relatively large diameter as compared with the stemof a poppet valve, and the great diiculty that has been encountered inforging together la tappet stem and head is the uncont-rollability ofthe hot metal during the forging operation. If

a. hollow stem is used, the flow of the metalconnot be controlledsatisfactorily, and there has been the danger that the exterior metal ofthe head would shear off the metal fin of the interior part. If a solidstem is used the metal containedl in the head usually forms into a ballor other irregularly shaped object and does not unite with the exteriorportion of the head. Such a formation is useless in a tappet oranalogous article.

In order to control the flow of the metal which composes the head, -andto obtain a highly efficient union between the stern and head of a twopiece .forged tappet, I have found that while the quantity of metal ofthe portion of the stem that enters the head should be no greater thanthat of the exterior portion of the head, it is essential -to provide asolid abutment for the exterior portion of the head to contact withduring the forgingfoperaton, and that by reason of the impact betweenthe two hot metals during the forging process, the two metals becomefusedtogether, thereby forming an integral connection between them.

Referring to Fig. 2, it will be seen that the end 10 of the stem 10enters the exterior metal portion 11il of the head, and that the endface-of the part 10a is concave and that the inner face of the exteriormetal part 11* is convex and conforms to the shape of the end of thepart 10, and is contiguous therewith. Beyond the'end part 1.0a the stemterminates in an annular, Widely flaring, rela# tively thin f n 10",which extends into the part of the disc like exterior head portion 11that overhangs the stem. The exterior and interior parts of the headbecome fused together during the forging operation, thereby formin anintegral structure in which the possibility of disconnectionbetween thehead and stem is completely eliminated.

In order to roduce the tappet structure just described,I form a stem.portion blank l0X (slee Figs. 4 to 7 inclusive) by cutting the properlength from a metal rod of suitable diameter, and bore out one endthereof as at 10y to leave a relatively thin annular wall 101. I alsoform a head piece blank 11x which contains a central bore or cavity 11ysurrounded by a relatively thin annular wall 11'. -The thickness of thebody portion 11F Aof the head blank and the thickness `of the annularwalls 10' 11, are carefully determined so that there may besubstantiallyno Waste when the head is forged up. The cavity of the head blank ismade deeper than that of the stem whereby the annular yvall 11'L of thehead blank may protrude below the bottom of the cavity 10". If desiredthe outer face of the stem around the wall 10" may be turned oli'slightly and the inner face of the wall 1'1z is made to t fairly well onthe wall 10. The two pieces 10x 11", are as sembled by placing the headpiece on the stem piece, and they are then heated to the forgingtemperature required for forging the head piece, which is considerablymore than that required for forging the stem,

especially when the head piece is formed of high speed steel or thelike.

The tivopieces are then placed in a die A, havin a suitable intagliodesign in its upper face or giving shape to the head, the die placed inthe anvil B of a suitable power hammer or other forging machine, and theupper die C (which is carried by the hammer arm of the hammer) broughtdown in a succession of blows upon the hot ieces, thereby spreading outthe metal whic protrudes from the-die A, and giving it the shape of thehead 11.

As the metal is pounded down and spread out, the annular wall 10z of thestem por- 'tion begins to flare outwardly and-over the wall 11z of thehead piece,and the bottom 'face 11l ofthe cavity 11"- comes into contactprocess, the metal'o the head portion is made denser than the steinportion and because of the high heatand the force exerted by the hammer,the two pieces are fused together into one integral mass whereby thepossibility of disconnection between the two is wholly eliminated. Inhammering down the metal after the bottom faces 10, 11 -become impacted,they take a concave-convex form as is roughly illustrated in thedrawing. This affords a thickened middle part for the exterior metal ofthe head. After the tappet is forged, it is bored, tapped and finishedas usual.

More or less variation of the exact details of construction is possible,without departing from the spirit of this invention; I desire,therefore, not to limit myself to the exact form of the constructionshown and described, but intend, in the following claims, to point outall of the invention disclosed herein.

I claim as new, and desire to secure by Letters Patent: y

1. A valve tappet comprising a disc like head portion and a stem,composed of two `pieces of metal, one piece forming the major andexterior portion' of the head, and the other piece forming the stem andinterior portion of thehead, the stem having a concave solid en'd partforming an abutment for the inner face of'the exterior portion of thehead and having, beyond said solid part, an annular, laterallyextending, relatively thin web portion projecting into the metal of theexterior portion'of the'head, the metal of the exterior portion of thehead being thickened at its middle and conforming gener ally to theshape of the adjacent concave end face of the stem part, and theexterior and interior parts of t-he head being integral with each other.y

2. A. valve tappet comprising a disc like head portion and a hollowstem. composed of two pieces of metal, one piece formingl the major andexterior portion of the head, and the other piece forming the hollowstemand interior portion of the head, the hollow stem having -a solidconcave end part at the head end forming an abutment for the exteriorportion of the head and having," beyond said solid part` an annular,laterally.

extending, relatively thin web portion projecting into the metal of theexterior portion of the head, the .metal of the exterior portion of thehead being thickened at its middle and con-forming generally to theshape of y stem and interior portion ofthe head, the 1 stem having asolid concave end. part forming an abutment for the exterior portion ofthe head and having. beyond said solid part, an annular, laterallyextending, relatively thin web portion projectin into the metal of theexterior portion of t 1e head, the exterior part of the head beingthickened towards itsmiddle and abutting against said concave end partof the stem, andthe exterior and interior parts of the head beingiintegral with each other.

4. A 'valve tappet comprising adisc like head portion and a stem,composed of two pieces of metal, one piece forming the major'andexterior portion of the head, and thev other piece forming the stem andinterior portion of the head. the stem having a solid, concave end partforming an .abutment for the exterior portion of the head andterminating in a widely iiaring, thin web which extends laterallyl intothe metal of the exterior portion of the head, the exterior portion ofthe head being thickened towards itsrniddle and the inner face of theexterior portion of the head conforming with they contiguous part of thestem contained in the head and being integral therewith.

5. A lvalve tappet comprising va disc like head portionl and a hollowstein, composed of two pieces of metal, one piece forming the major andexterior portion of the head, and the other piece forming the hollowstem and interior portion of the head, the hollow stem having a solid,concave end part forming an abutment for the exterior portion of thehead and terminating in a widely daring, thin web which extendslaterally into the metal of the exterior portion of-the head,

the exterior portion of the head being thickened towards'its middle andthe inner faceof the exterior portion of the head conforming with thecontiguous part of the stem contained in the head and being integraltherewith.

GEORGE R. RCH.

